1. What is Refrigerant Flow Rate?

Definition: This calculator determines the refrigerant flow rate in gallons per minute (GPM) based on heat load, latent heat of vaporization, and refrigerant density.

Purpose: It helps HVAC technicians and engineers properly size refrigeration systems and components.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Refrigerant flow rate (GPM)
• \( Q_{btu} \) — Heat load (BTU/hour)
• \( h_v \) — Latent heat of vaporization (BTU/lb)
• \( \rho_r \) — Refrigerant density (lb/gal)

Explanation: The heat load is divided by the product of latent heat, refrigerant density, and 60 (to convert from per hour to per minute).

3. Importance of Refrigerant Flow Rate Calculation

Details: Proper flow rate calculation ensures efficient system operation, prevents compressor damage, and maintains optimal heat transfer.

4. Using the Calculator

Tips: Enter the heat load in BTU/h, latent heat (default 100 BTU/lb), and refrigerant density (default 7.5 lb/gal). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical latent heat value for common refrigerants?
A: R-22: ~100 BTU/lb, R-134a: ~93 BTU/lb, R-410A: ~118 BTU/lb at typical conditions.

Q2: Why is refrigerant density important?
A: Different refrigerants have different densities which affects how much mass flows through the system per gallon.

Q3: How do I determine the heat load (Q_btu)?
A: Heat load can be calculated from temperature difference, flow rate, and specific heat of the medium being cooled.

Q4: What's the significance of the 60 in the denominator?
A: It converts the result from "per hour" to "per minute" since we're calculating GPM (gallons per minute).

Q5: Does this formula work for all refrigerants?
A: Yes, but you must use the correct h_v and ρ_r values for your specific refrigerant at operating conditions.